Surface electronic structure of bismuth oxychalcogenides

Abstract

Within density functional theory we study the bulk band structure and surface states of bismuth oxychalcogenides Bi 2 O 2 Se and Bi 2 O 2 Te. We consider both polar and nonpolar surface terminations. On the basis of relativistic ab initio calculations, we show that both unreconstructed (polar) and reconstructed (nonpolar) surfaces possess the Rashba spin-split surface states. The metallic Rashba-split states on polar surfaces stem from huge potential bending, positive or negative, depending on surface polarity. On the nonpolar surfaces resulting from single-crystal cleavage the emerging Rashba-split states are nonmetallic.

Valance Band Maximum and Thermoelectric Properties of Bi\(_2\)O\(_2\)Se: First-Principles Calculations

“…As can be seen, CBM occurs at Γ which is in good agreement with calculations reported previously [2,3,38]. The second-lowest points at the conduction band edges are at the L and M points.…”

“…Recently, bismuth dioxide selenide Bi 2 O 2 Se has been drawn much attention in the last few years in both theoretical and experimental studies including bulk and thin film [1][2][3][4][5][6]. It has been emerged as a promising candidate for future high-speed and low-power electronic applications due to the scalable fabrication of highly performing devices and excellent air stability and high-mobility semiconducting behavior [1][2][3][4]7]. The compound exhibits several characteristics (low thermal conductivity, high electrical conductivity, and high Seebeck coefficient) that would highlight its potential in a practical thermoelectric (TE) application.…”

“…The compound exhibits several characteristics (low thermal conductivity, high electrical conductivity, and high Seebeck coefficient) that would highlight its potential in a practical thermoelectric (TE) application. The electronic band structure determines the transport properties [3,[8][9][10], so even though the compound was initially described as being a n-type semiconductor, p-type doping is theoretically possible [2,11,12]. More studies are needed especially on band topology at the valence band maximum (VBM).…”

“…The electronic structure allows us to explore many basic properties [8,21], and plays a fundamental role in understanding materials. Detailed analysis of band structures at the valence band edge (especially the heavy band at the VBM) which determine the transport properties [3,7,22,23], are still lacking. The use of a conventional unit cell for the calculation may lead to the folding of the energy bands which may obscure important information.…”

Bi2O2Se:Bi2O5Se High‐K Stack as a 2D Analog of Si:SiO2: A First‐Principles Study

“…The bandgap value is calculated to be ≈0.6 eV, which is close to the experimental value. [ 30 ] This value is in between those calculated by the GGA‐PBE functional [ 39,50 ] and the Heyd–Scuseria–Ernzerhof (HSE06) hybrid functional. [ 39,48–50 ] Figure 1c,d shows the atomic structure and electronic structure of orthorhombic Bi 2 O 5 Se.…”